Congrats on your new ducklings. My Orpington hatched a duckling last year. I felt really bad having to take it from her but I did and gave it to my Muscovy who also hatched only one duckling. I know my Orpington would have been a great mama duck though. lol
She was the first to go broody this year so she now has her very own chicks.
I always give my mamas and their babies their own space inside the coop so they are safe but yet everyone can see them. Then once everyone comes out for the day mama and ducklings get the run of the coop. I do this for a week then I let mama and babies come out but I supervise, usually everyone respects mama and leaves the babies alone. But I still supervise just in case. At night mama and babies stay in their safe space until babies are at least 4 weeks old. I leave it up to mama when she wants to mingle the babies with the rest of the flock inside after 4 weeks. I have ducks and chickens sleeping in the same coop which means drakes and roosters too. I admit I am over protective.